Federal investigators are examining if there were any violations of federal law, “which includes potential civil rights violations such as hate crimes,” said U.S. Attorney Russell M. Coleman in Louisville.

Gregory A. Bush, 51, has been charged with murder and other crimes in the deaths of the man and the woman at a Kroger store Wednesday in Jeffersontown, located on the outskirts of Louisville. The FBI is investigating alongside local police.

“The murders are not being taken lightly by the United States government,” Coleman said in a prepared statement.

The information came as news media outlets reported that Bush made a racial comment after the deadly shooting in Jeffersontown, a city of about 26,600 people.

Rogers said it was too soon, however, to say whether the shooting was racially motivated.

Rogers said Bush apparently does have a history of mental illness, as news outlets have reported.

An arrest report says Bush walked into the Kroger, pulled a gun from his waist and shot a man in the back of the head, then kept shooting him multiple times “as he was down on the floor.” The report says Bush then reholstered his gun, walked outside and killed a woman in the parking lot. Each victim died of multiple gunshot wounds, Rogers said. Rogers said Bush was standing at arm’s length when he shot the woman in the back of the head.

A man carrying a concealed weapon who happened to be in the parking lot challenged Bush, and police say the suspect then “began firing wildly” at him, putting other shoppers in the parking lot in danger. Neither man was hurt in that confrontation, Rogers said.

Bystander video shows a white man in a distinctive neon-yellow shirt trying to drive away while an officer chases after him on foot. Many more officers converged on the scene and made the arrest just a few hundred yards (meters) from the store on Wednesday afternoon.

Bush was jailed on $5 million bond Thursday on two counts of murder and 10 counts of felony wanton endangerment.

Ed Harrell was quoted by the Courier Journal of Louisville as saying he was waiting on his wife in the parking lot when he heard gunshots and grabbed his revolver. As he crouched down, he said he saw the gunman walk “nonchalantly” by with a gun by his side. Harrell said he called out to ask what was going on, and the gunman replied: “Don’t shoot me. I won’t shoot you. Whites don’t shoot whites.”

Rogers said police “are aware of that statement and are evaluating any factors that may come into play with” it.

Bush’s ex-wife is African-American, and she has received protection orders against him after violent outbursts, including an incident in 2009 when she told police he called her racial epithets during a custody exchange of their son. They divorced in 2000.

The local coroner’s office identified Wednesday’s shooting victims as Maurice Stallard, 69, and Vicki Lee Jones, 67. Police said there didn’t appear to be any connection between Bush and the victims, or any link between Bush and the Kroger store.

Stallard’s 12-year-old grandson was shopping with him in the store when he was gunned down, Jeffersontown Mayor Bill Dieruf said Thursday. The boy was physically unharmed, but most certainly traumatized, the mayor said, adding, “He was there and cannot unsee what he has seen.”

Stallard was the father of Kellie Watson, the chief racial equity officer for Louisville Mayor Greg Fischer.

The mayor shared his outrage Thursday over what he called an “epidemic of gun violence” that “hit close to home.”

Authorities removed computers and cellphones from the house where Bush lived with his parents.

Bush’s criminal record shows he threatened his ex-wife and punched a deputy sheriff during a family court hearing years ago. He also was charged with assaulting his elderly parents in January 2009. A judge ordered him to comply with mental health treatment and prohibited Bush from possessing firearms for two years.

An arrest citation said Bush’s parents were punched and choked, and they told police they were “terrified of (his) unpredictable behavior.”

Bush’s ex-wife told authorities in a domestic violence petition in 2009 that Bush was “diagnosed paranoid” in 2003 but had stopped taking his medication.

“I am afraid for me and my son. I want him to stay away,” she wrote in the court document.